Sailors treated over contaminated water on HMS Portland warship

HMS Portland is pictured (foreground) tracking a Russian warship and tanker last month through the North Sea

A "small number" of navy personnel were taken to hospital after problems with water supplies on board their warship.

Submarine hunter HMS Portland returned to Portsmouth on Friday following a "contaminated water" incident.

A Royal Navy spokesperson said it was a "precautionary measure" after an issue with the ship's fresh water systems.

They said measures were being taken to "safeguard the ship's company" during investigations, with HMS Richmond on standby to provide any necessary cover.

It is thought that one of the crew members put the wrong chemical into the frigate's water system - designed to convert sea water into drinking water. The sailor, on realising the error, subsequently raised the alarm.

All those taken to hospital "are expected to make a full recovery", with the majority of those involved already discharged, a statement from the Royal Navy said.

"The recent issue with contaminated water in HMS Portland will be investigated thoroughly."

"We take the health and welfare of our people very seriously and will review processes to ensure this does not happen again," the statement added.

An investigation is now under way.

Nato mission

HMS Portland spent much of last year patrolling UK waters and, last July, co-operated with Nato allies on a submarine-hunting exercise in the North Atlantic.

It helped track two Russian submarines as they sailed into the North Sea along the Norwegian coast.

Last month it tracked a Russian warship as it sailed in international waters close to the UK.

The Type 23 frigate was commissioned in 2001 and over the years has been used in anti-drug missions in the Caribbean (2007) and deployed against pirates off the Horn of Africa (2009).

The ship also helped with disaster relief in Belize following Hurricane Dean in 2007.

It underwent a lengthy refit in 2021 which included an overhaul of machinery, computers and IT systems.